Abstract

                                The effect of the acaricide, hexythiazox 5.45 EC, known for its activity against eggs, and immature stages of spider mites, was evaluated in the laboratory against Tetranychus urticae Koch and Oligonychus biharensis Hirst, infesting grapes. O.biharensis was more susceptible than T.urticae. Hexythiazox 5.45 EC was highly effective against eggs of O.biharensis resulting in zero per cent egg hatch at 10 ppm itself on freshly laid eggs while in T.urticae zero per cent egg hatch occurred at 30 ppm only. The per cent egg hatch in untreated control ranged between 80.9 and 88.4 for different age groups of O.biharensis and T.urticae eggs. Toxicity on eggs depended on the age of eggs, freshly laid eggs being highly susceptible. Similar effects were observed in protonymphs also with more than 80 per cent mortality on the first day of treatment in O.biharensis and T.urticae, when leaf discs were treated at 30 ppm using spray method.

Key words : Hexythiazox 5.45 EC, ovicidal activity, O.biharensis, T.urticae, life stages